The invention relates to gas turbine engines. More particularly, the invention relates to casting of cooled shrouds or blade outer air seals (BOAS).
BOAS segments may be internally cooled by bleed air. For example, cooling air may be fed into a plenum at the outboard (OD) side of the BOAS. The cooling air may pass through passageways in the seal body and exit outlet ports in the ID side of the body (e.g. to film cool the ID face). Air may also exit along the circumferential ends (matefaces) of the BOAS so as to be vented into the adjacent inter-segment region (e.g., to help cool feather seal segments sealing the adjacent BOAS segments).
The BOAS segments may be cast via an investment casting process. In an exemplary casting process, wax may be molded in a die to form a pattern. The pattern may be shelled (e.g., a stuccoing process to form a ceramic shell). The wax may be removed from the shell. Metal may be cast in the shell. The shell may be destructively removed. After shell removal, the passageways may be drilled. Alternatively, some or all of the passageways may be cast using a casting core.